Work is continuing on the study of the possible functions of cell sequences that show homology to SV40 viral sequences, in particular we have found that the interspersed repetitive DNA consists of nucleotide stretches of about 265 bases showing strong homology with one another and showing some homology with the origin of replication of papovaviruses. These DNA sequences act as templates in vitro for polymerase III transcription and we are currently examining the RNAs produced in vivo that are homologous to these sequences and testing whether they also serve some role in the initiation of DNA replication.